CN116683193B - Frequency selective wave absorbing device with multiple switchable wave-transparent windows - Google Patents

Abstract

The invention discloses a frequency-selective wave absorbing device with multiple switchable wave transmission windows, including an active multi-pass band resistive layer and an active multi-pass band transmission layer located below the active multi-pass band resistive layer. The active multi-pass band resistive layer and the active multi-pass band transmission layer are fixed by non-metal pillars, thereby forming an air layer between the active multi-pass band resistive layer and the active multi-pass band transmission layer; The active multi-pass band-resistive layer includes a first dielectric plate (3) and a plurality of band-rejection frequency selective surface units (2) arranged above the first dielectric plate (3); the active multi-pass band transmission The layer includes a second dielectric plate (5) and a plurality of bandpass frequency selective surface units (4) disposed above the second dielectric plate (5). The invention can switch the wave transmission windows of multiple working frequency bands according to actual needs, and at the same time suppress interference signals outside the broadband in an absorbing manner while transmitting well in multiple working bands.

Description

A frequency-selective wave absorbing device with multiple switchable wave transmission windows

Technical field

The present invention relates to a frequency selective wave absorbing device, and in particular to a frequency selective wave absorbing device having a plurality of switchable wave transmission windows.

Background technique

With the rapid development of modern communication technology, equipment has increasingly diverse communication requirements for multiple frequency bands, which puts forward higher design requirements for protective materials such as radomes. These materials need to be transparent in multiple frequency bands to achieve good signal transmission; at the same time, when the equipment is not working, it can absorb out-of-band radio frequency interference to avoid electromagnetic compatibility problems caused by signal reflections from the metal structure of the equipment.

In radome design, the frequency-selective absorbing structure has obvious advantages because it has both absorbing and transmitting functions. However, the currently existing design methods can only control a single wave transmission window within the absorption zone and cannot meet the needs of multiple wave transmission windows.

Contents of the invention

The purpose of the present invention is to overcome the shortcomings of the prior art and provide a frequency-selective wave absorbing device with multiple switchable wave transmission windows, which can switch the wave transmission windows of multiple operating frequency bands according to actual needs. While transmitting well within a working band, it suppresses interference signals outside the broadband through absorption.

The object of the present invention is achieved through the following technical solution: a frequency-selective wave absorbing device with multiple switchable wave transmission windows, including an active multi-pass band resistive layer and an active multi-pass band resistive layer located below An active multi-pass band transmission layer, the active multi-pass band resistive layer and the active multi-pass band transmission layer are fixed by non-metal pillars, so that the active multi-pass band resistive layer and the active multi-pass band An air layer is formed between the belt transmission layers;

The active multi-pass band-resistive layer includes a first dielectric plate and a plurality of band-stop frequency selective surface units arranged above the first dielectric plate;

The active multi-passband transmission layer includes a second dielectric plate and a plurality of bandpass frequency selective surface units disposed above the second dielectric plate.

The beneficial effects of the present invention are: the present invention can switch the wave transmission windows of multiple operating frequency bands according to actual needs, and at the same time suppress interference signals outside the broadband in an absorbing manner while transmitting well in multiple operating bands.

Description of the drawings

Figure 1 is a schematic diagram of the device structure of the present invention;

Figure 2 is a schematic diagram of the band-rejection frequency selection surface unit;

Figure 3 is a schematic diagram of a resistive layer with line unit;

Figure 4 is a schematic diagram of the bandpass frequency selection surface unit;

Figure 5 is a schematic diagram of the transmission layer line unit;

Figure 6 is a schematic diagram of the relationship between the diode switching state and the position of the embedded resonant pole;

Figure 7 is a schematic diagram of the S parameter and absorption rate frequency response curves of the active resistive layer in dual-band and single-band modes;

Figure 8 is a schematic diagram of the frequency response curve of S parameters of the active transmission layer in dual-band and single-band modes;

Figure 9 is a schematic diagram of the transmission-reflection coefficient simulation results under different switching states.

Detailed ways

The technical solution of the present invention will be described in further detail below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following description.

As shown in Figure 1, a frequency-selective wave absorbing device with multiple switchable wave transmission windows includes an active multi-pass band resistive layer and an active multi-pass band transmission layer located below the active multi-pass band resistive layer. layer, the active multi-pass band resistive layer and the active multi-pass band transmission layer are fixed by non-metal pillars, thereby forming air between the active multi-pass band resistive layer and the active multi-pass band transmission layer layer;

The active multi-pass band-resistive layer includes a first dielectric plate 3 and a plurality of band-rejection frequency selective surface units 2 arranged above the first dielectric plate 3;

The active multi-passband transmission layer includes a second dielectric plate 5 and a plurality of bandpass frequency selection surface units 4 arranged above the second dielectric plate 5 .

In the embodiment of the present application, the number of bandpass frequency selection surface units 4 is the same as the bandstop frequency selection surface unit 2 , and each bandstop frequency selection surface unit 2 corresponds to a bandpass frequency selection surface unit 4 .

As shown in FIG. 2 , the band-rejection frequency selective surface unit 2 includes four block metal layers arranged in sequence and aligned left and right, where the upper edge of the first block metal layer is in contact with the edge of the first dielectric plate 3 The rear edge is aligned, and the lower edge of the fourth bulk metal layer is aligned with the front edge of the first dielectric plate 3;

The first bulk metal layer and the second bulk metal layer are connected through a first chip resistor 9 , and the second bulk metal layer and the third bulk metal layer are connected through a first chip capacitor 10 Connection, the third bulk metal layer and the fourth bulk metal layer are connected through the second chip resistor 11;

The first bulk metal layer is also provided with a first opening that opens to the right. A first metal patch 8 is provided in the first opening. The upper end of the first metal patch 8 passes through the first PIN diode 12 Connected to the first bulk metal layer, the lower end of the first metal patch is connected to the first bulk metal layer through the second patch capacitor 13; a second metal patch is also provided on the right side of the first metal patch 8. Metal patch 14, the second metal patch 14 and the first metal patch 8 are connected through a choke inductor;

The fourth massive metal layer is provided with a second opening penetrating the left and right sides of the metal layer. The second opening divides the fourth massive metal layer into upper and lower layers. A connection hole is provided on the left side of the second opening to connect the fourth massive metal layer. The first bending strip line 21 of the upper and lower layers of four massive metal layers; a third metal patch 16 is provided in the second opening, and the upper end of the third metal patch 16 passes through the second PIN diode 17 and The fourth bulk metal layer is connected, and the lower end of the third metal patch 16 is connected to the fourth bulk metal layer through the third patch capacitor 18; a fourth metal patch is also provided on the right side of the third metal patch 16. Metal patch 19, the fourth metal patch 19 and the third metal patch 16 are connected through a choke inductor;

The first dielectric plate 3 is also symmetrically provided with a first metal strip line and a second metal strip line connected to both sides of the first bulk metal layer. The first metal strip line 6 and the second metal strip line 7 are both embedded. There are two choke inductors; the position of the choke inductor embedded in the first metal strip line 6 is symmetrical with the position of the choke inductor embedded in the second metal strip line 7; the first metal strip line 6 and the second metal strip line 7 are embedded in the choke inductor. The upper edge of the strip line 7 is on the same straight line as the upper edge of the first bulk metal layer.

In the embodiment of the present application, each band-rejection frequency selection surface unit 2 is arranged sequentially from left to right along the first dielectric plate 3, and each band-rejection frequency selection surface unit 2 is connected in sequence:

Except for the first band-stop frequency selection surface unit 2, the first metal strip line 6 included in each band-stop frequency selection surface unit 2 is connected to the second metal strip line of the previous band-stop frequency selection surface unit 2;

As shown in Figure 3, the active multi-pass band resistive layer also includes a plurality of resistive layer strip line units arranged below the first dielectric plate 3. Each resistive layer strip line unit corresponds to a band stop frequency. Select surface element 2;

Each resistive layer strip line unit includes a third metal strip line 23 and a fourth metal strip line 24 perpendicular to the arrangement direction of the bulk metal layer. The third metal strip line 23 and the fourth metal strip line 24 are respectively embedded with three metal strip lines. choke coil;

The third metal strip line 23 is located directly below the second metal patch 14 , and the first dielectric plate 3 is provided with a strip that penetrates the second metal patch 14 , the first dielectric plate 3 and the third metal strip line 23 first metal via hole 15;

The fourth metal strip line 24 is located directly below the fourth metal patch 19 , and the first dielectric plate 3 is provided with a strip penetrating through the fourth metal patch 19 , the first dielectric plate 3 and the fourth metal strip line 24 The second metal via hole 20 .

Similarly, each resistive layer strip line unit is connected in sequence, that is, except for the first resistive layer strip line unit, the third metal strip line 23 of each resistive layer strip line unit is connected to the third metal strip line 23 of the previous resistive layer strip line unit. The third metal strip line 23 is connected; the fourth metal strip line 24 of each resistive layer strip line unit is connected to the fourth metal strip line 24 of the previous resistive layer strip line unit.

As shown in FIG. 4 , the bandpass frequency selective surface unit 4 includes two rectangular metal strip lines 25 with the same structure and parallel to each other. The upper edge of the rectangular metal strip line 25 is connected to the rear surface of the first dielectric plate 3 The side edges are aligned, and the lower edge of the rectangular metal strip line 25 is aligned with the front edge of the first dielectric plate 3;

A fifth metal strip line 26 is provided between the two rectangular metal strip lines 25. One end of the fifth metal strip line 26 is connected to the first rectangular metal strip line through a choke inductor, and the other end of the fifth metal strip line 26 is connected to the first rectangular metal strip line through a choke inductor. One end is connected to the second rectangular metal strip line through a choke inductor; the left side of the first rectangular metal strip line is connected to a sixth metal strip line 27 through a choke inductor; the second rectangular metal strip line A seventh metal strip line 28 is connected to the right side of The edges are on the same straight line.

A third opening and a fourth opening are provided on the rectangular metal strip line 25, and the fourth opening is located below the third opening;

The opening direction of the third opening is to the right, and a fifth metal patch 29 is provided in the third opening. The upper end of the fifth metal patch 29 is connected to the rectangular metal strip line 25 through the third PIN diode 30. The lower end of the fifth metal patch 29 is connected to the rectangular metal strip line 25 through the fourth patch capacitor 31; a sixth metal patch 32 is also provided on the right side of the fifth metal patch 29. The patch 29 and the sixth metal patch 32 are connected through a choke inductor;

The fourth opening is the opening on the left and right sides of the rectangular metal strip line 25 that runs through it. The opening divides the rectangular metal strip line 25 into upper and lower layers. On the left side of the fourth opening, there is an opening connecting the upper and lower rectangular metal strip lines 25 . The two-layer second bending strip line 36 is provided with a seventh metal patch 33 in the fourth opening. The upper end of the seventh metal patch 33 is connected to the rectangular metal strip line 25 through the fourth PIN diode 34. The seventh metal patch 33 is The lower end of the patch 33 is connected to the rectangular metal strip line 25 through the fifth patch capacitor 35. An eighth metal patch 37 is also provided on the right side of the seventh metal patch 33. The eighth metal patch 37 It is connected to the seventh metal patch 33 through a choke inductor.

Each bandpass frequency selection surface unit 4 is arranged in sequence from left to right along the second dielectric plate 5 , and each bandpass frequency selection surface unit 4 is connected in sequence, that is, except for the first bandpass frequency selection surface unit 4, The sixth metal strip line 27 of each bandpass frequency selection surface unit 4 is connected to the seventh metal stripline 28 of the previous bandpass frequency selection surface unit 4;

The active multi-passband transmission layer also includes a plurality of transmission layer strip line units arranged below the second dielectric plate 5 , and each transmission layer strip line unit corresponds to a bandpass frequency selection surface unit 4 .

As shown in Figure 5, the transmission layer strip line unit includes two strip line units, each strip line unit corresponding to a rectangular metal strip line 25 in the bandpass frequency selection surface unit 4;

The first strip line unit includes an eighth metal strip line 38 and a ninth metal strip line 39. Both the eighth metal strip line 38 and the ninth metal strip line 39 are embedded with two choke inductors;

The eighth metal strip line 38 is located directly below the sixth metal patch 32 in the corresponding rectangular metal strip line 25; the second dielectric plate 5 has a hole penetrating through the sixth metal patch 32, the second dielectric plate 5 and the third metal patch 32. The third metal via 40 of the eight metal strip lines 38;

The ninth metal strip line 39 is located directly below the eighth metal patch 37 in the corresponding rectangular metal strip line 25 , and the second dielectric plate 5 has holes penetrating through the eighth metal patch 37 , the second dielectric plate 5 and The fourth metal via 41 of the ninth metal strip line 39;

In the transmission layer strip line unit, the eighth metal strip lines 38 of the two strip line units are connected, and the ninth metal strip lines 39 of the two metal strip line units are connected.

Similarly, each transmission layer strip line unit is connected in sequence, that is, except for the first transmission layer strip line unit, the eighth metal strip line 38 of the first strip line unit in each transmission layer strip line unit is connected to the previous transmission layer strip line unit. The eighth metal strip line 38 of the second strip line unit in the line unit is connected; the ninth metal strip line 39 of the first strip line unit in each transmission layer strip line unit is connected to the second strip line 39 in the previous transmission layer strip line unit. The ninth metal strip line 39 of the strip line unit is connected;

In the embodiment of the present application, the PIN tubes in the band-stop frequency selection surface unit 2 and the corresponding band-pass frequency selection surface unit 4 maintain synchronous switching, that is, the first PIN diode 12 in the band-stop frequency selection surface unit 2 and the band-stop frequency selection surface unit 2 are switched synchronously. The third PIN diodes 30 embedded in each rectangular metal strip line 25 in the pass frequency selection surface unit 4 maintain synchronization on and off; the second PIN diode 17 of the band rejection frequency selection surface unit 2 and each rectangle in the band pass frequency selection surface unit 4 The fourth PIN diode 34 embedded in the metal strip line 25 remains on and off synchronously;

And in this embodiment, the PIN diodes in different band-rejection frequency selection surface units 2 remain on and off synchronously, that is, the first PIN diodes 12 in each band-rejection frequency selection surface unit 2 maintain synchronous on-off, and each band-rejection frequency selection surface unit 2 maintains synchronous on-off. The second PIN diode 17 in unit 2 remains on and off synchronously;

On this basis, it can be obtained that the third PIN diode 30 embedded in the rectangular metal strip line 25 in each band-pass frequency selection surface unit 4 also maintains synchronous switching; the rectangular metal strip line in each band-pass frequency selection surface unit 4 25 The embedded fourth PIN diode 34 also maintains synchronization on and off.

Therefore, in fact, the band-stop frequency selection surface unit 2 has four states in total, and these four states are determined by the conduction and disconnection of the first PIN diode 12 and the second PIN diode 17, respectively:

That is, the first PIN diode 12 and the second PIN diode 17 are turned off at the same time, the first PIN diode 12 and the second PIN diode 17 are turned on at the same time, the first PIN diode 12 is turned on, the second PIN diode 17 is turned off, and the first PIN Diode 12 is disconnected, and the second PIN diode 17 is conducting;

The first opening and all devices in the first opening (including the left side wall of the first opening) can be regarded as a high-frequency resonator. The first PIN diode serves as the control device of the high-frequency resonator. The second opening and all devices in the opening (including the first bent strip line 21) can be regarded as a low-frequency resonator, and the second PIN diode serves as the control device of the low-frequency resonator; by switching the control level of the PIN, high/low frequency control is achieved The switching of the impedance state of the embedded resonator is implemented to achieve the switching of the passband state (wave transmission window switching state). When the embedded resonator generates a reactance pole, the absorbed resonant current is cut off, resulting in a passband, which is the opening of the wave transmission window. When the reactance value of the embedded resonator is low, it has little effect on the absorbed resonant current, so it has little impact on the incoming resonant current. The wave shows absorption and does not produce a passband, which means the wave transmission window is turned off;

Since the PIN tubes in the band-rejection frequency selection surface unit 2 and the corresponding band-pass frequency selection surface unit 4 remain on and off synchronously, the wave transmission window switches of each band-pass frequency selection surface unit 4 and the band-rejection frequency selection surface unit 2 maintain Synchronize,

Moreover, the PIN tubes of each band-rejection frequency selection surface unit 2 remain synchronized, so the wave transmission windows of each unit of the entire wave absorption device also remain synchronized. Therefore, through the on-off control of the PIN tube, the entire device can be realized based on the wave transmission window switch. Wave absorption control to achieve frequency selection;

That is to say, the present invention realizes the control of multiple units by adjusting the PIN tube bias state of each unit on the absorption layer (active multi-pass band resistive layer) and transmission layer (active multi-pass band resistive layer) of the wave absorbing device. Switch of the wave-transmitting window. When the wave-transmitting window is open, the window transmits waves efficiently; when the wave-transmitting window is closed, the window appears to absorb waves.

The structure of this application consists of an active multi-passband resistive layer and an active multi-passband transmission layer cascaded through an air matching layer. Among them, the resistive layer functions to absorb external waves in the band and controllably transmits useful signals from multiple transmitting windows; while the transmission layer functions to reflect external waves in the band and works together with the resistive layer to improve the wave absorption performance while controllably transmitting Transmits useful signals across multiple wave transmission windows. The resistive layer is usually based on a band-stop frequency-selective surface cell structure loaded with lumped resistance, while the transmission layer is based on a band-pass frequency-selective surface cell structure. The two layers are independently designed using band-stop or band-pass structures, and the passbands are adjusted to be consistent through parameter adjustment, thereby achieving the construction of a wave-transmitting window within the wave-absorbing band. However, this discrete design method has many limitations. Different resonant unit selections (band stop/band pass) are usually difficult to accurately match multiple passbands. If the switch design of multiple passbands is considered, discrete The design method makes the passband matching design more complex. The present invention can perform loss elimination, in which the basic structural diagram of the transmission layer is shown in Figures 2 and 3. The two-layer structure adopts a consistent metal strip unit configuration, in which the resistive layer is loaded with two lumped resistors (chip resistors) in the strip, as well as a central coupling capacitor (via lumped resistors) used to build resonance absorption. Capacitor implementation). Compared with the resistive layer, the transmission layer has removed the central coupling capacitor and lumped resistance required to build absorption resonance. At the same time, in order to enhance the out-of-band reflection capability of the transmission layer to achieve the effect of improving the wave absorption performance, the transmission layer The x-period of the layer is halved.

Resistive and transmission layers of the same stripe configuration. The advantage of the strip configuration lies in its polarization selectivity, that is, it produces a frequency-selective absorbing effect for electromagnetic waves whose polarization direction is parallel to the metal strip (y direction in Figure 2). For electromagnetic waves in the orthogonal direction (x direction in Figure 2), the effect is fully transparent. The method proposed by the present invention makes the design of frequency-selective absorbers more flexible. For dual-polarization application requirements, dual-polarization characteristics can be achieved by placing two sets of frequency-selective absorbers orthogonally;

In order to build a consistent passband, each unit of the resistive and transmission layers is loaded with consistent high/low frequency resonators. The PIN diode is integrated into the embedded resonator as an active control device. By switching the control level of the PIN, the impedance state of the high/low frequency embedded resonator is switched, thereby switching the passband state (wave transmission window switching state) . When the embedded resonator generates a reactance pole, the absorbed resonant current is cut off, resulting in a passband, that is, the wave transmission window is opened. When the embedded resonator's reactance value is low, it has little effect on the absorbed resonant current, so it appears to the incoming wave. Absorption, that is, the shutdown of the wave transmission window. Since the high/low frequency embedded resonance loading methods of the resistive layer and the transmission layer are completely consistent, their active control methods are also completely consistent.

In the embodiment of the present application, FIG. 6 shows the relationship between the switching state of the diode loaded on the high/low frequency embedded resonator and the embedded resonance pole position. Among them, ER1 is a high-frequency embedded resonator (Embedded resonator), and ER2 is a low-frequency embedded resonator. When the PIN tube on the high-frequency resonator is turned on, the reactance pole is located at f11. When the PIN tube is turned off, the reactance pole is located at f12. When the PIN tube on the low-frequency resonator is turned on, the reactance pole is located at f21. When the PIN tube is turned off When , the reactance pole is located at f22. In the present invention, as an example, f11 and f22 are set to 6 GHz, f21 is set to 3 GHz, and f12 is set to 8 GHz. By switching the state of the PIN tube loaded in the high/low frequency embedded resonator, the three frequency points are switched from the reactance pole to the small reactance, and the switching of the wave transmission window at the three frequency points can be realized. The method proposed by the present invention is not limited to the construction of three wave-transmitting windows. By adjusting the number of embedded resonators, more wave-transmitting windows can be realized.

In order to explain the working principle of the structure, the frequency response curves of the resistive layer and the transmission layer are analyzed separately. The frequency response curve of the resistive layer is shown in Figure 7. Figure 7(a) shows the transmission coefficient and reflection coefficient results of the resistive layer in the dual-band mode (the solid line is the transmission coefficient and the dotted line is the reflection coefficient). Figure Figure 7(b) shows the transmission coefficient and reflection coefficient results of the resistive layer in single mode (the solid line is the transmission coefficient and the dotted line is the reflection coefficient); Figure 7(c) shows the absorptivity results of the resistive layer in dual-band mode. ; Figure 7(d) shows the absorptivity results of the resistive layer in single mode. The passband operation mode can be switched between dual-band and single-band. At the same time, it can be obtained from the absorption rate curve that the outside of the passband shows a good wave absorption effect. The frequency response curve of the transmission layer is shown in Figure 8. Figure 8(a) shows the transmission coefficient and reflection coefficient results of the transmission layer in dual-band mode (the solid line is the transmission coefficient, the dotted line is the reflection coefficient, Figure 8(b) is The transmission coefficient and reflection coefficient results of the transmission layer in single mode (the solid line is the transmission coefficient, the dotted line is the reflection coefficient), the passband shows a switching state consistent with the resistive layer, and at the same time, the out-of-band shows a higher reflectivity, so The outside of the band can be used as a reflective floor for the resistive layer to improve the absorption effect outside the passband. In the passband where the resistive layer and the transmission layer are consistent, both layers show good transmission effects, so they are superimposed to form an in-band transmission band. .

The resistive layer and the transmission layer are combined through the air layer to obtain the broadband frequency selective wave absorbing device with multiple switchable wave transmission windows proposed in the present invention. The simulation results are shown in Figure 9. Figure 9(a) shows the transmission coefficient and reflection coefficient results of the overall structure in single-band mode. Figure 9(b) shows the transmission coefficient and reflection coefficient results of the overall structure in dual-band mode. By regulating the state of the PIN tube loaded on the structure, the structure can switch between dual-band transmission and single-band transmission. At the same time, the out-of-band reflection shows a suppression effect.

The design of the DC control link of the controllable embedded resonator proposed by the present invention is as follows: parallel wiring in the x direction on the back side of the dielectric board. In order to maintain the structure's fully transparent characteristics for orthogonal polarization, the impact of the DC control link on the radio frequency signal is suppressed by loading a choke coil. The control link only transmits DC control current and has no effect on radio frequency signals. The invention uses the transmission layer to remove the lumped resistance device that generates loss and the lumped coupling capacitor that generates wave-absorbing series resonance in the resistive layer. Therefore, the resistive layer and the transmission layer have the same unit configuration. This method brings more design flexibility to the inter-layer matching of multi-passbands; the present invention proposes a multi-level embedded resonator design method, loading the PIN tube on the embedded resonator. Within the resonator, an embedded resonator with controllable impedance is formed. By constructing a consistent high/low frequency controllable embedded resonator in the resistive layer and transmission layer, the reactance pole position of the embedded resonance can be flexibly designed to achieve flexible design of multiple controllable passbands, while achieving good performance outside the passband. Wave absorption performance.

The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims (7)

1. A frequency selective wave absorbing device having a plurality of switchable wave transparent windows, characterized by: the active multi-passband transmission layer is fixed between the active multi-passband resistive layer and the active multi-passband transmission layer through nonmetal columns, so that an air layer is formed between the active multi-passband resistive layer and the active multi-passband transmission layer;

the active multi-passband resistive layer comprises a first dielectric plate (3) and a plurality of bandstop frequency selective surface units (2) arranged above the first dielectric plate (3);

the band-stop frequency selective surface unit (2) comprises 4 block metal layers which are sequentially arranged and aligned left and right, wherein the upper edge of a first block metal layer is aligned with the rear side edge of the first dielectric plate (3), and the lower edge of a fourth block metal layer is aligned with the front side edge of the first dielectric plate (3);

the first block metal layer is connected with the second block metal layer through a first chip resistor (9), the second block metal layer is connected with the third block metal layer through a first chip capacitor (10), and the third block metal layer is connected with the fourth block metal layer through a second chip resistor (11);

the first block metal layer is also provided with a first opening with an opening to the right, a first metal patch (8) is arranged in the first opening, the upper end of the first metal patch (8) is connected with the first block metal layer through a first PIN diode (12), and the lower end of the first metal patch is connected with the first block metal layer through a second patch capacitor (13); the right side of the first metal patch (8) is also provided with a second metal patch (14), and the second metal patch (14) is connected with the first metal patch (8) through a choke inductance;

a second opening penetrating through the left side and the right side of the metal layer is formed in the fourth block metal layer, the second opening divides the fourth block metal layer into an upper layer and a lower layer, and a first bending strap line (21) for connecting the upper layer and the lower layer of the fourth block metal layer is arranged on the left side of the second opening; a third metal patch (16) is arranged in the second opening, the upper end of the third metal patch (16) is connected with a fourth block-shaped metal layer through a second PIN diode (17), and the lower end of the third metal patch (16) is connected with the fourth block-shaped metal layer through a third patch capacitor (18); a fourth metal patch (19) is further arranged on the right side of the third metal patch (16), and the fourth metal patch (19) is connected with the third metal patch (16) through a choke inductance;

the first dielectric plate (3) is also symmetrically provided with a first metal strap and a second metal strap which are connected to two sides of the first block-shaped metal layer, and the first metal strap (6) and the second metal strap (7) are embedded with two choke inductors; the position of the choke inductance embedded by the first metal strap wire (6) is symmetrical to the position of the choke inductance embedded by the second metal strap wire (7); the upper edges of the first metal strip line (6) and the second metal strip line (7) are positioned on the same straight line with the upper edge of the first bulk metal layer;

the active multi-passband transmission layer comprises a second dielectric plate (5) and a plurality of bandpass frequency selective surface units (4) arranged above the second dielectric plate (5).

2. A frequency selective wave absorbing device having a plurality of switchable wave transparent windows as defined in claim 1, wherein: the number of band-pass frequency selective surface units (4) is the same as the number of band-stop frequency selective surface units (2), and each band-stop frequency selective surface unit (2) corresponds to one band-pass frequency selective surface unit (4).

3. A frequency selective wave absorbing device having a plurality of switchable wave transparent windows as defined in claim 1, wherein: the active multi-passband resistive layer further comprises a plurality of resistive layer stripline units arranged below the first dielectric plate (3), each resistive layer stripline unit corresponding to one bandstop frequency selective surface unit (2);

each resistive layer strip line unit comprises a third strip line (23) and a fourth strip line (24) which are perpendicular to the arrangement direction of the bulk metal layers, and the third strip line (23) and the fourth strip line (24) are respectively embedded with three choke coils;

the third metal strap (23) is positioned under the second metal patch (14), and the first dielectric plate (3) is provided with a first metal via hole (15) penetrating through the second metal patch (14), the first dielectric plate (3) and the third metal strap (23);

the fourth metal strap (24) is located under the fourth metal patch (19), and the first dielectric plate (3) is provided with a second metal via hole (20) penetrating through the fourth metal patch (19), the first dielectric plate (3) and the fourth metal strap (24).

4. A frequency selective wave absorbing device having a plurality of switchable wave transparent windows as defined in claim 1, wherein: the band-pass frequency selection surface unit (4) comprises two rectangular metal strip lines (25) which are identical in structure and parallel to each other, wherein the upper edges of the rectangular metal strip lines (25) are aligned with the rear side edges of the first dielectric plates (3), and the lower edges of the rectangular metal strip lines (25) are aligned with the front side edges of the first dielectric plates (3);

a fifth metal strip line (26) is arranged between the two rectangular metal strip lines (25), one end of the fifth metal strip line (26) is connected with the first rectangular metal strip line through a choke inductor, and the other end of the fifth metal strip line (26) is connected with the second rectangular metal strip line through the choke inductor; wherein the left side of the first rectangular metal strip line is connected with a sixth metal strip line (27) through a choke inductor; the right side of the second rectangular metal strip line is connected with a seventh metal strip line (28) through a choke inductor; the upper edges of the fifth metal strip line (26), the sixth metal strip line (27) and the seventh metal strip line (28) are positioned on the same straight line with the upper edge of the rectangular metal strip line (25).

5. A frequency selective wave absorbing device having a plurality of switchable wave transparent windows as defined in claim 4, wherein: a third opening and a fourth opening are arranged on the rectangular metal strip line (25), and the fourth opening is positioned below the third opening;

the opening direction of the third opening is rightward, a fifth metal patch (29) is arranged in the third opening, the upper end of the fifth metal patch (29) is connected with the rectangular metal strip line (25) through a third PIN diode (30), and the lower end of the fifth metal patch (29) is connected with the rectangular metal strip line (25) through a fourth patch capacitor (31); a sixth metal patch (32) is further arranged on the right side of the fifth metal patch (29), and the fifth metal patch (29) and the sixth metal patch (32) are connected through a choke inductance;

the fourth opening is an opening on the left side and the right side of the penetrating rectangular metal strip line (25), the opening divides the rectangular metal strip line (25) into an upper layer and a lower layer, and a second bending strip line (36) for connecting the upper layer and the lower layer of the rectangular metal strip line (25) is arranged on the left side of the fourth opening; the seventh metal patch (33) is arranged in the fourth opening, the upper end of the seventh metal patch (33) is connected with the rectangular metal strip line (25) through the fourth PIN diode (34), the lower end of the seventh metal patch (33) is connected with the rectangular metal strip line (25) through the fifth patch capacitor (35), the eighth metal patch (37) is further arranged on the right side of the seventh metal patch (33), and the eighth metal patch (37) is connected with the seventh metal patch (33) through a choke inductance.

6. A frequency selective wave absorbing device having a plurality of switchable wave transparent windows as defined in claim 5, wherein: the active multi-passband transmission layer further comprises a plurality of transmission layer stripline elements arranged below the second dielectric plate (5), each transmission layer stripline element corresponding to one bandpass frequency selective surface element (4).

7. A frequency selective wave absorbing device having a plurality of switchable wave transparent windows as defined in claim 5, wherein: the transmission layer stripline units comprise two stripline units, each corresponding to one rectangular metal stripline (25) in the band-pass frequency selective surface unit (4);

the first strip line unit comprises an eighth strip line (38) and a ninth strip line (39), and the eighth strip line (38) and the ninth strip line (39) are embedded with two choke inductors;

the eighth metal strip line (38) is positioned right below the sixth metal patch (32) in the corresponding rectangular metal strip line (25); the second dielectric plate (5) is provided with a third metal via hole (40) penetrating through the sixth metal patch (32), the second dielectric plate (5) and the eighth metal strap line (38);

the ninth metal strip line (39) is located right below the eighth metal patch (37) in the corresponding rectangular metal strip line (25), and the second dielectric plate (5) is provided with a fourth metal via hole (41) penetrating through the eighth metal patch (37), the second dielectric plate (5) and the ninth metal strip line (39);

in the transmission layer stripline unit, eighth striplines (38) of the two stripline units are connected, and ninth striplines (39) of the two stripline units are connected.